4-(betahydroxyethoxy-2-hydroxy-benzophenones) and esters thereof

ABSTRACT

Compounds of the formula WHEREIN R is hydrogen, alkyl or aryl and R&#39;&#39; is hydrocarbyl acyloxy, said compounds being useful for light-stabilization of polymeric compositions.

Umted States Patent [15] 3, Eggensperger et a]. [451 July 11, 1972 [54]4-(BETAHYDROXYETHOXY-2- 1 References Cited HYDROXY-BENZOPHENONES) ANDUNITED STATES PATENTS ESTERS THEREOF 2,448,767 9/1948 Carlson ..260/284[72] Inventors; Heinz Eggensperger, Gademheim ub r 2,980,647 4/1961Lappin .260/45.85 Bensheim; volker Franzen, Heidelberg; et a1. KIKolmbach uber Bensheim l Goldberg et al. all Of Germany 2,675,367 4/ l954 Caldwell ..260/47 3,322,817 5/1967 Goldberg et al. ....260/475 1AS98999 Deutsche Advance Produkflon Gmbn 3,086,988 4/1963 Gordon....260/488 Lautemlodenwald, Germany 3,313,866 4/1967 116mm et al..260/880 22 Filed: Oct. 28, 1968 Prlmary Exammer-Lems Gotts APPI-NW771,272 Assistant Examiner-Diana G. Rivers Attorney-Christen & Sabol[30] Forelgn Appllcatlon Prlorlty Data ABSTRACT Dec. 21, 1967 Germany..P 16 43 307.1 Compounds ofthe formula 52 us. Cl. ..260/410.5,260/45.85, 260/45.9 R,

260/45.95, 260/457, 260/465 D, 260/465 R, R R 260/469, 260/470, 260/476R, 260/481, 260/485 0, C

260/486 R, 260/487, 260/488 CD, 260/946, 1

260/591 4 51 Int. Cl. ..C07c 69/28 C076 49/82, C08f45/58 [58] Field 68Search ..260/410.5, 591,45.85,488 CD, R hydmgen alkyl and R hydmarby'260/485 G, 476 R, 469 US, 486 R acyloxy, said compounds being useful forlight-stabilization of polymeric compositions.

8 Claims, No Drawings 4-(BETAHYDROXYETHOXY-Z-HYDROXY- BENZOPHENONES) ANDEST ERS THEREOF The invention concerns new compositions of thebenzophenone series, which are suited as light stabilizers for polymers,new intermediates for forming such new compositions and methods forpreparing same.

It is known to add UV absorbers to polymers for protection against thedetrimental effects of light. The best known products used for thispurpose are, possibly compounds of the benzophenone or benzotriazoleseries substituted with halogen or alkoxy groups.

In practice it has been found that the stabilizing effects of these UVabsorbers can be substantially increased if their characteristics suchas volatility, solubility, etc. are adapted as far as possible to thespecific requirements in each case, to the extent permitted by thepreparation and other characteristics of the polymer to be stabilized.The above-mentioned known compounds of the benzophenone andbenzotriazole series allowed such adaptation only to an insufficientextent, because the variation possibilities of these systems were verylimited and confined only to the use of alkyl groups and halogens.

It was found that the variation capability of the compounds of thebenzophenone series can be greatly expanded and that new and veryeffective light stabilizers can be prepared if 2,4-dihydroxybenzophenone of formula I is reacted in the presence of basiccatalysts, preferably alkali or alkaline earth metal carbonates oralcoholates, and organic solvents with ethylene carbonate or ethyleneoxide, to produce compounds of formula ll according to the followingequation:

Catalyst HOCHz-CHzO -OH H (II) II t It was surprising to discover thatin this reaction the hydroxyl group in the 4 position almost exclusivelyreacted. The compound of formula I] obtained thereby can be chemicallymodified much more widely than previously known light stabilizers of thebenzophenone and benzotriazole series and can, therefore, also be betteradapted to the specific requirements of the system to be stabilized. Themodification for obtaining best results is obtained by etherification oresterification of the aliphatic hydroxyl group of compound II withorganic alcohol radicals or organic or inorganic acids. According to thechoice of etherification or esterification agent the compatibility,volatility and/or extractibility of the final product can be easilychanged to the desired degree.

As organic acids the following can be used according to the invention:straight chain or branched, saturated or unsaturated, monocarboxylic orpolycarboxylic acids, which can be substituted by thioether groups,halogens, other functional groups such as cyano or hydroxyl groupsand/or phenol groups substituted by hydroxyl groups, or aromatic acids.

Some examples of the esters of compound II with organic acids are:benzoic acid ester, 2,6-dimethyl4-hydroxybenzylthioglycolic acid ester,crotonic acid ester, bis- (thiodipropionic acid) ester, and cyanoaceticacid ester of the 4-(beta-hydroxyethoxy-2-hydroxybenzophenone).

Some examples of inorganic acids that can be used are hydrohalogenicacids, e.g., hydrochloric acid and hydrobromic acid, hydrocyanic acids,phosphoric acid and sulfuric acid.

linking two or By the use of monovalent inorganic acids ormonocarboxylic acids to esterify compound II; or by etherification ofthe corresponding halide, i.e., formula III below wherein R is halogen,e.g., chlorine, with an organic etherifying agent, e.g., sodium,potassium or other alkali metal alkoxides; or by reaction of suchcorresponding halides with phosphites or salts of the formula, (R"O) Por (R"O POM wherein R" is alkyl, cycloalkyl or aryl and M is alkalimetal, for example; there are obtained compounds of the formula:

it I

wherein R is a monovalent acid, alcohol or phosphonate radical such asthe halogen, the cyano, or the acyloxy group derived from the monovalentacid, or the alkoxy, cycloalkoxy or aryloxy group derived from themonohydric alcohol or the phosphonate radical (R"O) P(O) Theabove-mentioned acyloxy, alkoxy, cycloalkoxy and aryloxy groups can beunsubstituted or substituted with halogen, cyano, hydroxyl, hydroxyaryl,e.g., hydroxyphenyl, or thioether groups. Preferably the R groupcontains up to and including 18 carbon' atoms; for example, where Rcontains carbon atoms it, preferably contains one to 18 carbon atoms.

Examples of organic alcohol radicals represented by R include theorganoxy radicals of monohydric alcohols such as methanol, ethanol,octanol, stearyl alcohol, benzyl alcohol, cyclohexanol and othersubstituted and unsubstituted alcohols. Radicals of polyhydric organicalcohols are useful in more of the ethyleneoxy-substituted benzophenonegroups shown in formula III.

Illustrating the process, 1 mole 2,4-dihydroxybenzophenone of formula Iis suitably heated together with 2.2 moles ethylene carbonate and 10 gsodium methylate in about 700 cc dialkyl ketone for about A to 1 hour atabout 140C and after completion of the reaction, the reaction product isstirred into about 1 liter water. Thereupon the product is acidifiedwith concentrated hydrochloric acid, the ketone is separated off,remaining solvent is distilled off and the residue is esterified oretherified or otherwise reacted as explained above without necessarilybeing subjected to further intervening treatments. The yield of finalproduct usually amounts to about percent.

The esters, ethers and phosphonates obtained according to the inventionare generally suited for light stabilization of synthetic polymers suchas polyolefins, polyvinyl chloride and their copolymers with otherunsaturated compounds, polystyrene and its copolymers with butadiene,acrylonitrile and/or methacrylic acid esters, polyesters, polyamides aswell as synthetic resin lacquers.

The stabilizers of the invention are commonly used in amounts of 0.1 to10 percent calculated on the total weight of the polymeric material tobe stabilized.

The following examples are presented.

(III) EXAMPLE 1 Stearic acid ester of4-(beta-hydroxycthOxy-Z-hydroxybenzophenone) Stabilizer l 855 g (4moles) 2,4-dihydroxybenzophenone were heated together with 800 g (9moles) ethylene carbonate and 50 g sodium methylate in 400 cc diisobutylketone for 50 minutes at C, quickly cooled to room temperature andstirred into 3 liters water. After acidifying'with concentrated l-lClthe ketone was separated out and the aqueous phase washed twice, eachtime with 500 cc dichlorethane. The organic phases were combined, thesolvent distilled off in vacuum. The residue was a compound having theformula [I wherein R is hydrogen. The residue was heated under refluxfor 3 hours for esterification with 1,200 g (4.2 moles) stearic acid in1.5 liters toluene with the addition of 20 g p-t'oluenesulfonic acid ascatalyst. The toluene was washed with water, dried and distilled off invacuum. The residue was dissolved in 2 liters hot isopropanol and againprecipitated out by beginning the crystallization with 12 litersmethanol. The yield was 1930 g of the stearic acid ester of the formula111 wherein R is stearoyloxy and R is hydrogen. This was a yield of 92.5percent of the theoretical, calculated on the 2,4-dihydroxy benzophenoneused. Melting point was 66 to 68C.

EXAMPLE 2 Propionic acid ester of 4-(beta-hydroxyethoxy)-2-hydroxy-4-phenylbenzophenone Stabilizer 2 58 g (0.2 mole)2,4-dihydroxy-4-phenylbenzophenone, 40 g (0.4 mole) ethylene carbonateand 5 g sodium methylate were heated in 400 cc diisobutyl ketone for 2hours at 130C. The reaction mixture after cooling was stirred in waterand cc concentrated HCl. The organic phase was separated out. Theaqueous phase was extracted twice with methylene chloride. The solventwas distilled off in vacuum and the residue was recrystallized twicefrom methanol.

Yield 60 g of (4-beta-hydroxyethyoxy-2-hydroxy-4-phenylbenzophenone).This yield was 84 of the theoretical. Melting point: 157 to 158C.

By esterification of this alcohol with propionic acid by known methodssuch as described in Example 1, stabilizer 2 is obtained.

Yield:

108 percent, calculated on the alcohol used and 84 percent, calculatedon the 2,4-dihydroxy-4-pheny1- benzophenone used.

The compounds listed in Table l were obtained in an analogous manner,which compounds are characterized by their substituents R and R withreference to the general formula 111.

TABLE 1 Stabilizer 1 (illustrates invention) 10 produce the intermediateof formula 11 wherein R is phenyl.

Thereafter, the intermediate was reacted with, respectively, propionicacid and decanoic acid in the manner set forth in Examples 1 and 2.

EXAMPLE 3 Light stabilizing of polypropylene To each 100 parts ofunstabilized polypropylene powder there were added 0.5 parts2,6-di-tert.butyl-p-cresol and 0.2 parts of the light stabilizers listedin Table 2 below. All these mixtures were rolled on a laboratoryroll-mill at 180C for 10 minutes. The foils obtained were then pressedin a press at a pressure of 200 atm. and a temperature of 210C for 8minutes. From all the 1 mm thick plates so obtained, 5 strips were cutfrom each. The strips were illuminated by storage in the Xenotestapparatus.

The brittleness of the samples were tested and results are given inTable 2.

TABLE 2 Light protective agent Brittle after 3 0 hours2-hydroxy-4-octoxybenzophenone (comparison) 1000 Commercial UV absorberof triazone type (comparison) 1000 1200 Melting Compound point, Yield,Number R R R H C. percent 3 H C2H5CO O Propanoic acid 57-58 85 1. HCnHzaCO 0' Laurie acid. 52-53 83 5. H C17H35COO Stearlc acid 66-68 92 6H -C O 0- Benzoic acid 97-99 70 7 H Q-Q-CO O 4-phenylbenzoic acid118-120 CH; CH;

8 H HO- CHzS CHzC 00- HO- CH2SCHCOOH -75 74 I CH 3 CH3 CH= CH-COO-Cinnamic acid 112-114 CHIl-CH CHCOO- 2-butenoic acid 70 O O C- C C-C O0- 2-butynedioic acid... 'OOCCHZCHzSCHzCHzCOO' Thiodipropionic acid 67CN CHzCO O- Cyanoacetic acid. R6 BlCHzCOO Bromoacetic acid 00 (C2Hi0)z1fz aoh l 35 C11 0" Methanol 40-41 75 Br Hydrobromic acid -95 78 CnHasCOO'Stcuric 101d 06-157 87 10 CzH5COO' Propanoic acid 103-104 84 20 CuH CO 0Decanoic acid 85-86 81 In the manufacture of compounds 3 through 17,2,4- dihydroxybenzophenone was used as a starting material to producethe intermediate of formula 11 wherein R is hydrogen. Thereafter, theresulting intermediate was reacted with the EXAMPLE 4 75 Lightstabilizing of polyvinyl chloride To each 100 parts of PVC suspension ofK value 65 there were added 2 parts of a barium/cadmium lauratestabilizer and the light protective agents indicated in Table 3. Themixtures were rolled out in the same way as described in Example 3 on aroller at 180C for 5 minutes to 0.3 mm thick foils, which wereilluminated at 55C in the same fadeometer apparatus.

wherein, when R is selected from the group consisting of alkyl and arylhaving up to 18 carbon atoms, R is hydrocarbyl acyloxy having 10 to 18carbon atoms and, when R is hydrogen, R is selected from the groupconsisting of benzoyloxy, cinnamoyloxy, 4-phenylbenzoyloxy, and (OOCC ECCO )l/2.

2. The compound of claim 1 wherein R is phenyl and R is decanoyloxy.

3. The compound of claim 1 wherein R is hydrogen and R is cinnamoyloxy.

4. The compound of claim 1 wherein R is hydrogen and R is4-pheny1benzoyloxy.

5. The compound of claim 1 wherein R is hydrogen and R is benzoyloxy.

6. The compound of claim 1 wherein R is methyl and R is stearoyloxy.

7. The compound as claimed in claim 1 wherein R is hydrogen and R is(OOC--C E C-C0O--) 8. The compound of the formula wherein R is phenyland R is propionyloxy.

2. The compound of claim 1 wherein R is phenyl and R'' is decanoyloxy.3. The compound of claim 1 wherein R is hydrogen and R'' iscinnamoyloxy.
 4. The compound of claim 1 wherein R is hydrogen and R''is 4-phenylbenzoyloxy.
 5. The compound of claim 1 wherein R is hydrogenand R'' is benzoyloxy.
 6. The compound of claim 1 wherein R is methyland R'' is stearoyloxy.
 7. The compound as claimed in claim 1 wherein Ris hydrogen and R'' is (-OOC-C*C-COO-)1/2.
 8. The compound of theformula wherein R is phenyl and R'' is propionyloxy.